Electronic equipment (such as, for example, television sets and other audio/video equipments) are commonly implemented using digital technology instead of analog technology. Typically, the more advanced the digital technology gets the more demanding the task of converting an analog signal to a digital signal suitable for the digital technology implementation becomes.
Conceptually, an analog-to-digital converter (also denoted ADC or A/D converter) is very well know in the art as well as its basic functionality (sample-and-hold, quantization) and will not be elaborated on further herein.
For high sampling frequencies it may be necessary or at least beneficial to use ADC structures comprising several constituent ADC:s to be able to accommodate the high sampling frequency. Such structures alleviate the processing speed requirements on each constituent ADC. Examples of such ADC structures are pipe-lined ADC:s and time-interleaved ADC:s (e.g. parallel successive ADC:s). US 2011/0304489 A1, WO 2007/093478 A1, EP 0624289 B1 and WO 2010/042051 A1 describe various example time-interleaved ADC structures.
In a typical application of analog-to-digital conversion, it may be desirable to digitize two or more analog input signals wherein the corresponding digital signals should have different sampling rates and/or different resolution in each sample. This may be solved by using a separate ADC for each of the signals.
For example, in an audio/video application (processing of e.g. an audio input signal and three (RBG) video input signals) the video signal(s) typically require much higher sampling rates than the audio signal(s). The audio signal may typically be sufficiently processed (and even oversampled to achieve high dynamics) by a non-time-interleaved ADC, while each of the video signal(s) may require a time-interleaved ADC having several constituent ADC:s. Another example is in vehicle-related applications, where signals from a large number of sensors (and/or similar signal sources) may need processing with diverse ADC requirements.
A solution with a separate ADC for each of the signals may, however, not be eligible in all situations. For example, having each time-interleaved ADC designed for a particular type of signal, rate, and/or resolution may be inflexible and/or inefficient. For example, an architecture designed for one audio channel and three video channels may be unsuitable to use in a situation with four audio channels and vice versa.
Therefore, there is a need for more flexible time-interleaved analog-to-digital converters.